The present invention relates to a spinal support rod kit for the treatment of spinal column shape deformations.
Support rods which are used to support a spinal column can be fastened to the patient's vertebrae by means of fastening devices such as for example by bone screws or hooks. The support rods can help to support the spine in a desired alignment, for example during fusion of vertebrae.
Support rods are deformed prior to fixation to a patient's vertebrae, and forces are then applied to the vertebrae as the rods attempt to recover elastically toward their original undeformed configuration. Deformation of the rods can involve application of bending stresses and of torsional stresses. When it is desired to apply forces to a patient's spinal column through torsional deformation of a support rod, it can be preferred that the support rod has a non-circular cross-section, especially a square cross-section, which can be fitted into a channel in a fixation device whose cross-section is such that twisting of the rod in the channel is inhibited.
Maintaining a torsional deformation in a support rod requires that the rod is received in appropriate fixation devices at spaced apart points along its length. When this is done by fitting the rod into a channel in a fixation device with an appropriate non-circular cross-section, it can be difficult to locate the fixation device appropriately having regard to the variation in the cross-section of the rod as presented to the channel and the available vertebral tissue to which the fixation device might be fitted. This difficulty can be particularly acute in the thoracic region.